1. Field of the Invention
The present invention relates to agricultural machinery, and, more particularly, for apparatus and methods for determining the level of grain within a grain tank.
2. Description of the Related Art
As the agricultural technology is evolving there is an ever increasing drive towards efficiency. This drive for efficiency is apparent in the use of agricultural combines to harvest even greater quantities of grain or crop material for a given pass through the field. The combine harvests, collects and processes the crop to extract the grain which is placed in a grain tank for accumulation until it is full at which point it is discharged into another vehicle for transport from the field. It becomes important to have 1) a reliable means of determining the level of grain within a tank so that delivery to a transport vehicle only takes place when the grain tank is full and 2) means to determine the exact level, and, by association, the rate the grain tank is filling so that the time to fill can be predicted.
This has prompted a number of approaches to determine fullness within the tank. An early approach was a window giving a visual indication to the operator when the tank is nearly full. However, this posed a distraction to the operator who is called on to operate a large and increasingly complex piece of machinery. Other approaches have been to have pressure level switches at various locations within the tank to provide an indication when the tank is, for example, ¾ full and then full. Other devices using ultrasonic or radar detectors have been proposed. While these do provide a means of determining the fullness within the grain tank, they do so at increased cost and complexity.
Accordingly, what is needed in the art is a simplified and effective way to continuously measure the increase in quantity of grain within a grain tank.